Russian President Vladimir Putin and President Donald Trump are expected to meet in some format at next month's G-20 summit in Germany.

Speaking Wednesday at a news conference in the Russian city of Krasnodar, Russian Foreign Minister Sergei Lavrov said he would "assume" the meeting will take place.

"Given that the two presidents will be in the same town at the same time, same building, even the same room. It wouldn't be normal if they didn't talk," Lavrov told reporters.

If Trump and Putin meet at the conference, it will be the first time the two leaders have met face-to-face since Trump's election in November.

Putin said in March he was ready to meet with Trump at the G-20 meeting, though neither Washington nor Moscow have confirmed an official meeting.

Lavrov said the most important topic of potential discussion during the meeting would encompass the normalization of relations between the two nations, and that efforts to find a peaceful solution to the conflict in Syria would play a prominent role in that conversation.

Should the U.S. take preemptive measures against the Syrian military to stop what Washington has said could be a potential chemical weapons strike, Lavrov said Russia would respond "with dignity" to the U.S. "provocation."

The U.S. said earlier this week it had detected potential preparations for a chemical attack at Syria's Shayrat airfield, which was used in April to launch a chemical attack that killed more than 80 people in Khan Sheikhoun.

On Wednesday, Defense Secretary Jim Mattis said Syria appeared to have heeded a U.S. warning to not to use chemical weapons.

"It appears that they took the warning seriously," Mattis said, referring to the regime of Syrian President Bashar al-Assad, saying it had not launched any new chemical attacks.

Lavrov said U.S. Secretary of State Rex Tillerson called him and informed him of the alleged Syrian government plot to use chemical weapons, but Lavrov said he urged the U.S. against using the allegations as a "pretext" for war.

"I am very hopeful that this time around the U.S. will still be guided by the need to really protect the regime of non-proliferation of chemical weapons rather than speculating on dubious intelligence, which is secret and must not be shown to anyone," Lavrov said.